The possibility of photochemical smog formation is more at

Photochemical smog is formed when nitrogen oxides (NO₂) and volatile organic compounds (hydrocarbons) react in the presence of sunlight to produce secondary pollutants like ozone, PAN (peroxyacetyl nitrate), and other irritants.

The key requirements for photochemical smog formation are:

1. Nitrogen oxides (from automobile exhaust and industrial emissions)

2. Hydrocarbons (from incomplete combustion of fuels)

3. Sunlight (for photochemical reactions)

4. Warm, stagnant air conditions

Industrial areas have high concentrations of both nitrogen oxides and hydrocarbons from factories, vehicles, and other sources. Combined with sunlight, these areas have the highest possibility of photochemical smog formation.

The correct answer is Industrial areas.